Puma Biotechnology (NYSE:PBYI): PBYI received an upgrade from analysts at Stifel Nicolaus last Monday, raising its price target to $42 — 35% higher than the company’s previous closing price. The company’s metastatic breast cancer treatment, PB272,is in Phase II of clinical trials. The stock responded with a 16% jump, closing the week at $33.39.

Ariad Pharmaceuticals (NASDAQ:ARIA): Shares of Ariad fell 8% last week, continuing a downward trend that started on March 14. Ariad’s chairman and CEO, Harvey Berger, sold 105,400 shares of stock mid-March, fulfilling plans he had set in place in December 2012. Investors took this as a bearish sign, and the stock has been falling ever since. The company, which produces the myeloid leukemia treatment Iclusig, closed the week at $18.08.

Array BioPharma (NASDAQ:ARRY): Array’s shares jumped last week in response to an upgrade from Piper Jaffray. The company was rated “overweight” last Monday on expectations that it will report favorable Phase II trials for KSP inhibitor ARRY-520, and its melanoma treatment MEK-162 will begin Phase III trials. Shares of Array rose 14% last week, closing at $4.91.

Idenix Pharmaceuticals (NASDAQ:IDIX): Idenix took a hit last week after being deemed the junior party to Gilead Sciences (NASDAQ:GILD) in a hepatitis C treatment patent application. The decision does not determine which company was first to invent the compounds under development, but it’s still a reason for concern. Shares of IDIX closed at $3.54 on Thursday, a drop of 23% on the week.

Cadence Pharmaceuticals (NASDAQ:CADX): Shares of Cadence climbed last week after new coverage from JMP Securities, assigning the stock an “outperform” rating. The company, maker of acetaminophen injection OFIRMEV, has been moving toward a one-year high since mid-November. Shares closed at $6.69 on Thursday — a gain of 17% for the week.

Adam Benjamin is Assistant Editor of InvestorPlace.com. As of this writing, he did not hold a position in any of the aforementioned securities.